The present invention relates to a system for distributing a digital content such as software, digital publication or the like and a method for protecting a digital content from illegal copying.
In recent years, the distribution of game software or software programs (hereinafter referred to as software) by CD-ROM or network to users has begun to become prevalent and popular in association with the lowering of the cost of CD-ROMS and the consolidation of network environments. At the same time, the provision of information by CD-ROM or network to subscribers has also begun to become popular with the advance of digitization of information. Information thus provided includes text information such as a digital newspaper or publication, multimedia title information created through the composite use of still pictures or images, and so forth. In the present invention, a work produced assuming the distribution and use thereof as digital information as mentioned above is called digital content. It may be considered that a service for not only the distribution of such a digital content through CD-ROM or network but also the occasional updating or version-improvement of the digital content will appear in the future.
In a system for distributing such digital contents, a scheme for protecting the right of a producer of a work (hereinafter referred to as digital author) and effecting the proper payment of counter values such as digital content use charges from users to the digital author is important. So far as the environments in which digital contents can be distributed without anxiety are not consolidated, the author will be kept troubled with illegal uses.
In the conventional superdistribution technique, an accounting is performed using a security system in which plain texts (or decrypted information) are obtained only in a dedicated processor incorporated in an equipment. Namely, the frequency of use of information is calculated regarding the use as being made each time a decrypting process is performed by the dedicated processor. This frequency of use is occasionally sent to an accounting center and the accounting center side collects a charge corresponding to the frequency of use from a user. Since the distributed information is all encrypted, the copy thereof itself is not worthy of use. In order to use the information, it is necessary to decrypt it by the dedicated processor. Each time the decryption is performed, the frequency of use is counted. As a result, the payment of a counter value for use is materialized. A digital content distribution system based on such a method is generally called superdistribution system. U.S. Pat. No. 5,410,598 issued to V. H. Shear discloses a database usage metering and protection system.
The conventional superdistribution system includes a problem that there is a need to incorporate the dedicated processors into all users"" equipment and the accounting center performs an accounting management including the one-by-one collection of use frequencies counted by the dedicated processors, which makes the whole of the system complicated and therefore makes the cost of introduction of the system high. The superdistribution system is rather high in cost as a scheme for implementing, for example, digital newspapers or digital publications. Taking the case of the newspaper by way of example, on-time information is important and the use such as repeated reading is uncommon. A contract such as the current newspaper (in a paper form) subscription contract by the month is preferable than a contract based on the frequency of use. That is, a digital newspaper by the superdistribution system becomes higher in cost by a value corresponding to the use frequency management and the accounting management at the accounting center. The superdistribution system is rather suitable for the case where legacy digital documents are utilized at a digital library or the like. Namely, it can be said that the superdistribution system is suitable for an accounting management based on a so-called meter rate system but becomes high in cost as a method for implementing applications aimed at a fixed rate system.
An object of the present invention made for solving the above problem is to provide a digital content distribution system in which the use of the illegal copy of a digital content can be prevented and the digital content can expediently be utilized by a user.
Another object of the present invention is to provide a system which facilitates the version-up or updating feature of a digital content for a user.
A further object of the present invention is to provide a digital content distribution system which is suitable for a fixed rate system with a charge for use of a digital content fixed irrespective of the frequency of use.
A digital content protection system for a present invention for reading a digital content from a communication network and processing it includes a drive system for making an access to information in a storage medium mounted thereto, a judging section connected to the drive system for reading a code from a predetermined location on the storage medium to judge whether or not the location exists in a read only storage area and to judge whether or not the code matches with a predetermined code (key), and a digital content access permitting section for permitting the decoding of the digital content read through the communication network, the permission being made when it is determined as the result of judgement by the judging section that the location is in the read only storage area and the code matches with the predetermined code. The digital content access permitting section decodes a program included in the digital content and executes the decoded program. The digital content read through the communication network is stored in a rewritable area of the storage area and is updated by the program stored in the read only storage area. The information about the predetermined location and the predetermined code which are used in the judging section are also read through the communication network and are stored in a rewritable area of the storage medium. In order to optically judge whether or not the location exists in the read only storage area, the judgement is made of whether or not a light beam reflection factor of the location of the storage medium is higher than a predetermined value. The storage medium may have a plurality of different keys in the read only storage area so that a distributor can transmit to the communication network that one of a plurality of location addresses which corresponds to the date.
A storage medium according to the present invention includes a read only storage area in which a predetermined code is stored at a predetermined storage location and a rewritable storage area in which a digital content is stored. A method of the present invention performed by a computer includes a step of reading a code from a predetermined storage location of a storage medium to judge whether or not the storage location exists in a read only storage area of the storage medium and to judge whether or not the code is a predetermined code, and a step of reading, when the storage location and the code are valid, a digital content from a rewritable storage area of the storage medium for program execution or data reference. With this method, since the computer checks the existence of the predetermined code in the read only storage area, it is possible to eliminate an illegal copy of the digital content by a storage, medium the whole of which is a rewritable storage area.
Also, a digital content distributing system according to the present invention is composed of a terminal system for performing the reading and writing of information for a storage medium and a distributor connected to the terminal system through a network for distributing a digital content, the terminal system being provided with means for reading information from the storage medium and writing information into the storage medium, first processing means for reading a code from a predetermined storage location of the storage medium to judge whether or not the storage location is in a read only storage area of the storage means and to judge whether or not the code string is a predetermined code, second processing means for reading, when the storage location and the code are valid, a digital content from a rewritable storage area of the storage medium for program execution or data reference, and third processing means for requesting the distributor to transmit the latest edition of the digital content and storing the acquired latest edition into the rewritable storage area of the storage medium, and the distributor being provided with processing means for transmitting the latest edition of the digital content to the terminal system in response to the request from the terminal system. With this system, since a storage medium, the whole of which is a read only storage area, cannot be subjected to the writing of the latest edition of a digital content when the digital content is version-improved, it is possible to restrict the use of an illegal copy on the storage medium. Also, even in the case where a digital content is illegally copied into a storage medium which includes a read only storage area and a rewritable storage area as in the storage medium of the present invention, it is possible to prevent the illegal acquisition of the digital content in such a manner that the distributor checks a user profile code such as a contract code, personal code, password or the like of a user of the digital content and the number of times of distribution when the distribution receives the request of the latest edition from the terminal system.
As mentioned above, a storage medium of the present invention can prevent the use of an illegal copy of a digital content. In the other words, it can be understood that the use of the digital content is restricted to a storage medium for which a contract for use of the digital content is concluded.
The number of predetermined codes stored in the read only storage area is not limited to one. A plurality of codes can be stored so that a code to be referred to for the certification of the storage medium is changed in accordance with a term of validity of the digital content. With the construction in which the plurality of codes are set, it is possible to provide a trial term for a digital content or to change a code to be checked in accordance with the term of validity.
Also, with a construction in which a user profile code used for the user certification when a user acquires the latest edition of a digital content is stored in a rewritable storage area of the storage medium of the present invention or in another memory so that it is automatically transmitted from a terminal system to a distributor, it is possible to save on labor and time for inputting the user profile code for the certification of a user. Namely, either in the case where an access is made to a digital content in the storage medium of the present invention or in the case where an access is made to a digital content possessed by the distributor, it is not necessary for the user to perform a specific operation for the certification. In other words, the possession of a dedicated storage medium acts, by itself, as the certification in the use of a digital content, thereby making it possible to save that labor and time for the certification for each access. With a construction in which a user profile code is registered into the distributor side or updated thereon in accordance with a request from the terminal system to the distributor, a user himself or herself can set and register at least a part (for example, a password) of the profile code and can change into the distribution side at least a part of the profile code in accordance with a security environment.
A system using a digital content is not limited to the terminal system which is connected to the distributor through the network. Instead of acquiring the latest edition of the digital content through the network, there can be used a distribution relay system with which the updating of the digital content using a removable storage medium is possible. Such a distribution relay system reads a code from a predetermined storage location of the storage medium to judge whether or not the storage location is in a read only storage area of the storage medium and to judge whether or not the code matches with a predetermined code. When the storage location and the code are valid, the distributor relay system reads a digital content from a memory and stores the read digital content into a rewritable storage area of the storage medium. The storage medium having the latest edition of the digital content thus stored therein can be used by a user through a storage medium reading unit of an information processor (or computer).
A function required for the information processor includes at least the storage medium reading unit, processing means for reading a code from a predetermined storage location of the storage medium to judge whether or not the storage location is in a read only storage area of the storage medium and to judge whether or not the code is a predetermined code, and processing means for reading, when the storage location and the code are valid, a digital content from a rewritable storage area of the storage medium for program execution or data reference. Thereby, a small-size and low-cost system as an information processor using a digital content can be implemented.
In the present invention, the term of validity of a digital content can be set in the read only storage area of the storage medium. The information processor reads this term of validity to check whether or not the present date is included in the term of validity. Namely, the purchase of the storage medium ensures the acquisition of the latest edition of the digital content to the user for a fixed term of validity.
According to the present invention, since the check of whether or not a storage medium is valid is made using a storage medium composed of a read only storage area and a rewritable storage area as mentioned above, it is possible to prevent the use of an illegal copy of a digital content. Also, the present invention provides a digital content distribution system in which the purchase of a storage medium materializes a contract for use and the latest edition of a digital content can thereafter be acquired expediently by use of the same storage medium. Further, the present invention makes it possible to easily acquire the latest edition of a digital content from a distribution center through a network or from a distribution relay system through the storage medium.